Delta has a very long history of being bought and sold by various companies. I think that their web site has a somewhat abbreviated history of the company, but if you go to the Vintage Machinery site, I think that there might be more detailed information, also possibly Wikipedia.
When I first became interested in Delta woodworking machines, they were a division of Pentair and I believe that their headquarters was still in Pittsburgh, PA. Prior to that they had been a part of Rockwell International and headquartered in Milwaukee, WI and the Delta name had been dropped and the machines were branded as Rockwell. Pentair acquired Invicta a Brazilian manufacturer. Invicta manufactured some of the machines like trhe big jointer and planers which were branded Invicta Delta. I have a jointer and a planer that are Invicta Delta machines.
I think that it was somewhere in the early or mid 1990's that Delta moved from Pittsburgh to Memphis, TN. At about the same time, most of the manufacturing went to Taiwan, ROC. I have a Delta Unisaw that I got in the early 1990's that is labeled as "Made in USA", but I know that most of the cast iron parts were made in Taiwan.
Around ten years ago Pentair sold Delta to Black & Decker which also owned the DeWalt name and had also acquired Porter-Cable in Jackson, TN. It wasn't too much later that Delta moved from Memphis to Jackson so that it was collocated with Porter-Cable. As far as I know, Porter-Cable tools continued to be made in the USA, but I think that the Delta tools were mostly made in Taiwan, Mexico, and other countries outside the USA. Approximately five years ago Stanley acquired Black & Decker and decided to spin off Delta which had been on the decline ever since being treated like an unwanted stepchild by Black & Decker. A group of Taiwan investors were interested in reviving the Delta name so they bought the tooling and whatever else was left of Delta and moved it to Anderson, SC.
I think that when B&D combined Delta, DeWalt, and Porter-Cable, some the branding was changed and depending on what type of saw you are talking about, it might have originally been branded as a DeWalt saw. In addition to the Unisaw which was Delta's flagship cabinet saw, they also made a couople smaller cabinet saws as well as some contractor style saws. DeWalt also had some contractor style saws. However, I think that all of the contractor saws were 7 or 8 inches whereas the Delta cabinet saws were all 10 inches. Based on the age of the two saws, I am certain that neither is made in the USA.